what would you do with 100000000000000000000000000000000000000000000000000000000000 dollars and 75 cents?

So now you've moved on from tredecillions to sexdecillions. That much money would be entirely electronic in nature, in that you're now talking about a number that is literally larger than all the atoms in the universe. I suppose if any one person came into that amount of money, it would (being electronic, after all) indicate an intense and radical result of economic inflation, it would be common for average people to be earning undecillions each year, and there would be a lot of quattuordecillionaires and quindecillionaires around. Thus your hypothetical sexdecillion would have about as much buying power as a billion or so does today...so I would do with it what billionaires do with their billions today.

I won't want that much money.

I would spend all but the 75 cents.

buy my own island and some nice clothes

i would buy the world

Buy a pack of chewing gum and a third world country.